This invention concerns hollow fibers, and more particularly, hollow fibers co-spun with a core within the hollow portion of the hollow filament useful as separation devices or for bioreactor applications and spinnerets for co-spinning such fibers.
Hollow-fiber membrane bioreactors are known and have utility in the production of materials from suspended or immobilized enzymes or cell cultures. Cells or enzymes are located within or outside of the hollow fibers with reaction substrates being supplied to the cells or enzymes while desired products are removed. Cell cultures encompass aerobic or anaerobic cells as well as photosynthetic plant or bacterial cells. Due to the compact proportions of a bioreactor, known manual methods of manufacturing such membranes are costly and time consuming, particularly when dual hollow filaments of extended length and fine diameter are involved. Another limiting factor in the efficient operation of a bioreactor is the ability to deliver the proper levels of substrates into the system. These substrates include nutrients for cell growth, cofactors for efficient enzyme function, light for photosynthetic reactions and precursor materials for the desired products. In addition, it is known that various energy sources (electrical, mechanical, light, thermal) can regulate cell growth, enzyme activity, membrane permeability and subsequently have a significant effect on the control or efficiency of a bioreactor.